[phpisthebest]

You are not splitting a timer between 2 files

you are splitting a service and a timer, not all services need a timer. I think that is point being glossed over

services may be called by a target, a timer, or manually. or all 3 when the need arises.

So for example if I have a process that I need to run on startup, every Friday, and sometimes adhoc I can create a single service file and do all 3, and know it is executed in the same way every time

could not do that with cron or even older init systems